Summary for the Administrative Supplement Any two, unrelated people have up to 10,000 amino acid differences among their proteins. To identify which are medically-relevant, current computer predictions make assumptions that are based, in part, on evolutionary information for each protein. However, these assumptions were derived from experiments that were heavily biased by substitutions at positions that do not change much during evolution (conserved). We previously found that these assumptions do not apply to the >50% of amino acid positions that are not conserved during evolution. We are using pyruvate kinase and aldolase as model systems to explore hypotheses about the origins of non-canonical functional outcomes that arise from substituting nonconserved positions. Our experi- mental results will lead to improved ?rules? for new computer analyses. Our experimental design requires the creation and characterization ~1000 amino acid variants, and a floor-model centrifuge is required for this work. We recently learned that Thermo-Fisher has discontinued support for all of the centrifuges owned by our lab and our department, and the centrifuge in our lab has broken. Therefore, we are requesting $32,000 to purchase a new model and compatible rotors.